Switch operating mechanism



Aug. 7, 1934- c. THUMIM SWITCH OPERA TING MECHANISM Original Filed Sept 4, 1931 2 Sheets-Sheet l Inventov: Cowl Thumim,

bg His Abbov'neg.

Aug. 7, 1934. c. THUMIM SWITCH OPERA TING MECHANISM Original Filed Sept. 4, 1931 2 Sheets-Sheet 2 T L W 9 a i 7 v Q 5 $1 m... 16 H Patented Aug. 7, 1934 UNITED STATES PAT ENT .oFricE eral Electric Company,

York

a corporation of New Original application September 4, 1931, Serial No. I 561,215; Divided and this application November 12, 1932, Serial No. 642,396 I 4 Claims. (01. 1s5 43 My invention relates to switch operating mechanism, more particularly to opening and closing mechanisms for large capacity circuit breakers.

A principal object of my invention is the provision of improved means for preventing improper manual operation of switch-operating mechanism of the energy storing type.

This application is a division of my copending application, Serial Number 561,215, filed September 4, 1931, for Switch operating mechanism.

The mechanism disclosed and claimed in my aforesaid application provides for circuitbreaker opening and closing operations which are independently controlled by separate energy storing devices, as strong compression springs, the springs being operatively connected through cam mechanism or the like to suitable motive means for the purpose of effecting an energy 7 storing operation on the springs. The springs, which may be designatedas the opening and closing springs, are held in the charged or compressed-positions thereof by corresponding latching and tripping means, which are in turn separately controlled torelease the springs and cause opening or closing of the circuit breaker as the case may be. Forthe purpose .of insuring proper sequence of operation of the mechanism, the tripping means controlling the release of the opening and closing springs are associated with mechanical interlocking means arranged so that neither spring may beztripped during the spring charging operation, which may be effected simultaneously on both springs, and also that release'of the closing spring to close the breaker must occur prior to release of the opening spring.

In accordance with the present invention the spring charging means when operated manually is rendered inoperative for further charging and is positively blocked when the spring charging operation iscomplete; 1

My invention will be more fully set forth in the following description referring 'to the accompanying drawings, and the features of 'novelty which characterize my invention willbe pointed outwith particularity in the claims annexed to and forming a part ofthis specification. 1

tional view, partly in section, of switch-operating mechanism embodying my invention in the fully spring-charged open circuit position thereof; Fig. 2 is a partial view of the mechanism shown in Fig. 1 in the closedcircuit po- Referring to the drawings, Fig. 1 is an e1evasition thereof; Fig. 3 is a similar View showing the mechanism in the open circuit position prior to resetting of the trip and latching means; and Fig. 4 shows the mechanism in the open circuit position at the beginning of the spring charging operation with the latch and tripping means reset.

Referring to Fig.' 1, the circuit breakers (not shown) are operatively connected in any well known manner to the switch operating rod 1 so that downward vertical movement of the rod effects circuit closing and corresponding upward movement causes opening of the circuit. Circuit breakers of the type to which the present invention is applicable are large and massive in construction so that both the opening and closing operations require great force. Particularly is. this true of the closing operation wherein the massive linkage and contact structure must be moved into position against compression of the usual springs (not shown) associated with the breaker mechanism. Although the circuit breaker contacts. may be normally biased towards open circuit position, it is essential that a powerful initial accelerating force be applied if the contacts are to be separated within the'few cycles required in the case of a short circuit.

The switch-operating rod 1 is arranged to be actuated, in a manner hereinafter described, by a set of powerful closing springs 2 and an opening spring 3, the springs 2 and 3 being operatively connected to the electric motor 4 through suitable reduction gearings 4' and 5 and cams 6 and '7 respectively, the gear 5 and, cams 6 and 7 being mounted on a common shaft 5'. Energization of the motor 4 in a predetermined manner causes clockwise rotation of the cams 6 and 7 and charging of the closing and opening springs so that subsequent release of the springs is eifective to actuate the switch rod 1. I e

For the purpose of restraining theoclosingand opening springs inthe charged or energy storing position until the switch rod 1 is to be actuated, the springs 2 and 3 are individually. re lated to the latching and tripping means 8. and 9 respectively, the arrangement being such' that actuation of the trip '8 causes release of the closing springs 2 and downward'or circuit closing movement of the switch rod 1 and actuation of the trip 9 causes simultaneousrelease of the switch rod 1 and opening spring ;3 which produces a strong accelerating force to move the switch rod 1 upwardly to open circuit position.

Referring more particularly to the closing springs, there are provided relatively movable opposing blocks and 11 between which the springs 2 are seated. The lower block 11 is provided with suitable openings through which extend in sliding relation the spring guide rods 12 which are secured to the upper block 10. The block 11 is pivotally connected as at 13 to a lever 14 provided at its free end with a roller 15 bearing on the actuating face of the cam 6 and pivoted at its other end at 16 to the stationary frame (not shown). It is apparent that counterclockwise movement of the lever 14 by the cam 6, assuming the block 10 to be stationary, causes the block 11 to move upwardly with respect to guide rods 12 and to compress springs 2. The block 10 is held stationary when the springs 2 are compressed by the tripping and latching means 8 above referred to, the block 10 being operatively connected through toggle linkages to the means 3. The tripping and latching means comprises a tripping solenoid l? and a latch or prop 18 arranged to be engagedby'a roller 19 carried at the free end of a toggle link'ZO. The link 20, having a stationary pivot 21, forms one portion of the tripping toggle whose common pivot is at 22 uniting the link to the link 23. The tripping toggle 20--23 is connected to the block 10 by a crank 24 having a fixed pivot 25, a curved link 26 pivotally connected as at 2'? to a crank 24, and as at 28 to a crank 29 which is likewise mounted'on a fixed pivot 36 and is pivotally connected to the block 15 at 31. In the charged position'of the springs 2 as illustrated in Fig. 1 the block 10 is held'stationary by the underset toggle 20 23 and toggle 24-26, movement of the prop 18 in a clockwise direction causing: collapse of the toggles under the bias of springs 2. The consequent clockwise rotation of the crank transmits corresponding movement to the crank 32 having a fixed pivot3 3, through the links 3 1 and 35which are pivotally united by pin 36. The crank 32, hereinafter referred to as the closing crank, is pivotally connected to the switch rod 1' and is provided with a roller 37 formingthe lower extremity of the rod 1.

The opening spring 3, which is likewise mounted between a pair of relatively movable bearing blocks 33 and 39, is charged by counterclockwise rotation of the crank 40 pivotally mounted on the frame at 41 and provided with a roller 42 hearing on the actuating face of the cam 7. The crank 46 is pivotally connected as'at 43 to a flange forming part of the bearing block 39 which 'is provided with suitable apertures through which the spring guide rod 14 extends in sliding relation thereto. Assuming that the upper block 38 is held stationary, counter-clockwise rotation of the crank 40 is efiective to raise the block 39 and compress the closing spring 3. As in the case of the closing springs, the opening spring is likewise held in the charged position by the tripping and latching means 9 comprising thetripping solenoid 45 and latch 46 arranged to'be biased in a clockwise direction by the solenoid 45. The tripping toggle 4"1-4.3, which is held in underset position by the latch 46 as the previousinstancads connected to "the block 33 by a'linkage comprising crank l9, curved'link 50 and'crank 51. The crank' 51, which rotates about the stationary pivot 52 is pivotally connected at its shorter lever arm as at 53- to the block 38, and at it's longer lever arm at 54 to the link 50. The roller 37 forming the lower end of the switch rod 1 is directly in alignment with the block 38 and abuts the upper surface of the block when the mechanism is in the closed circuit position as illustrated in Fig. 2. As in the case of the opening trip toggle, actuation'of the latch 46 in a clockwise direction by its actuating solenoid 45 releases the roller 48' causing collapse of the toggle 47-48 due to the forces exerted by the circuit breaker on switch rod 1 and by the spring 3 which rotates the crank 51 in acounter-clockwise direction and urges the switch rod 1 upwardly towards open circuit position.

A connection, jior ,a purpose hereinafter explained, is provided between the tripping toggle 47-48 and the pivot pin 36 joining the thrust links 34 and 35 comprising a link 55 having a slot 56 in which the pin 36 is free to slide. This lost motion connection is necessary by reason of the relative lengths of lever arms of the cranks 51 and 32. V i

In apparatus of this character it is essential that the operation be carried out in a predetermined sequence. For example, it should be impossible to trip either the opening or closing springs during the spring charging operation and to trip the opening spring prior to tripping of the closing spring. Energization of the motor to recharge the springs should likewise be prevented except in the case where the circuit breaker is open and'both' springs discharged.

For this purpose there is provided positive mechanical interlocks for precluding tripping of the springs except in a predetermined order, and auxiliary switches for controlling energization'of the-motor. The mechanical interlocking means comprises a lever 57 pivotally mounted as at 58 and provided at one end with a roller 59 hearing on the actuating'face of the interlock controlling cam 60 which is mounted on: the shaft 5'. The lever57 is normally biased asby spring'61 into engagement with the cam surface and is connected through a'pin connection 62 to a rod 63 mounted for vertical reciprocal movement in a stationary guide. The rod 63 is connected through a pin and slot connection 65 to a pivoted locking lever 66 associated with the latch 1 8 and is in sliding engagement through a lost motion connection with a member 67. A pin connection 68 connects the member 6'7 with the pivoted locking lever 69 which is associated with the latch 46. The rod 63 abuts the end of a recess 6'7 in member 6'7 in which it slides after a certain upward movement to' cause'rotation of the lever 69 to its'locking position whereas lowering of the rod 63 is inefiective by itself to change the position of said locking lever.

In the position illustrated in Fig. 1, the inter lock actuating lever 57 engages the low side or notch 60 of the interlock cam 60 so that the rod 63 is biased downwardly by the-spring 61 and the locking lever 66 permits free actuation of the latch 18. In this position the rod '63 is lowered within the recess 67', the locking lever 69 being maintained in its'locking position by a pivoted prop 70. When the latch 46 is locked out by the lever 69, it will be noted that energization of the solenoid 45 is ineffective to cause release of the opening spring. I In order that the locking lever69 shall be released only after release of the closing springs, the prop '70 is'provided with an offset lug '71 directly in the path of the toggle link 20. Itwill be apparent that collapse of the ice toggle 20-23 as indicated in Fig. 2 in response to release of the closing spring causes the link 20 to rotate the prop in clockwise direction to release the locking lever 69 which in turn rotates in a counter-clockwise direction under the influence of gravity or suitable biasingmeans' to the position illustrated in Fig. 2.

The auxiliary switches controlling energization of the motor 4 comprises a limit switch 72 controlled in accordance withthe positions of the spring charging and interlocking cams, and a switch-73 controlled in accordance with the position of the opening spring block 38. The limit switch '72 comprises a stationary contact '74 and a pivotally mounted contact 75 normally biased, as by spring '76, towards closed position. Suitably mounted on the gear 5 is a lug 77 arranged to bias contact '75 to open position when the cams are in the position shown in Fig. l. The auxiliary switch 73 comprises a fixed contact '78 and a contact 79 carried by the block 38 arranged so that the contacts are in engage,- ment, as illustrated in Fig.-3,'when the opening spring is released. It will be noted that the switch '73 is in shunt with limit switch '72 so that energization of the motor from the supply source 80 may be effected by closing either. switch '72 or 73.

In order to reduce or minimize the impact-due to release of the closing and. opening springs, there are provided suitable shock absorbing means, as buffersprings. To this end the block 10 has secured thereto a pair of depending bolts 81 on which a pair of bufier springs 82 are mounted. The springs seat at one end on the,

disks 83 held in position by the nuts 84 and are arranged to engage the stationary guide memers 85 when the block 10 is projected upwardly a predetermined distance by the springs 2. The buffer for the opening spring comprises a spring 85 seated between a portion 87 of the block 39 and a disk 88 slidable with respect to the guide rod 44 and abutting an annular shoulder 89 likewise forming part of the-block 39. .When the spring 3 is released, the guide rod 44 which is carried upwardly by the block 38 engages the disk 88, by means of nut 90, thereby trans mitting the opening impact after a. predetermined upward movement of the block 38 to the buffer spring 86. v

' The operating cycle of the motor mechanism is as follows:

When the mechanism is in the spring. charged open circuit position illustrated in Fig.1 the motor circuit is open through both auxiliary switches 72 and 73, and the interlockingjmeans through the locking lever 69, looks out the tripping latch of the switch rod 1 and opening spring 3. The latch 18 of the closing spring is however operative and when it is desired to close the circuit breakers, the operator, through a suitably arranged push button control or the like, energizes the solenoid 17 to release the latch 18 and cause collapse of the toggle 20-23. occurs the closing springs 2, which are supported by the roller 15 on the cam 6, project the block 10 upwardly with a powerful thrust. to cause straightening of the toggle 3555 and clockwise rotation of crank 32, lowering the switch rod 1 to the closed circuit position shown in Fig. 2. It will be noted that during clockwise rotation of thecrank 32 the pin 49 connected to the link 55 is held stationary so that links 35 and 55 operate as a thrust toggle. .7 The closedcircuit position of the mechanism When this wherein the closing springs are discharged and the opening spring still charged is shown in Fig. 2. "It will be noted that immediately after actuation of the closing tripping toggle, the opening spring latch is no longer-locked out and release of the opening spring may take place. This is trueeven though the closing operation hasv not been completed since the initial collapse of the closing spring toggle 2023 actuates the prop 70' and releases the locking lever 69. The mechanism is therefore mechanically trip-free after initiation of the circuit closing operation and electrically trip-free when the, circuit breaking contacts engage.

In the event that the opening spring is tripped during the circuit closing operation, the pin 49 is, released by tripping of the latch 46 and moves counterclockwise out of its thrust transmitting position so that the energy of the springs 2is dissipated by the buffer springs 82. By this arrangement wherein the link 55, through the pin 36, maintains'the links 34, 35in thrust-transmitting position while the opening spring is held latched, the application of the closing force to, the switch rod 1 is immediately removed in response to trip-free action'so'that the switch rod is not subjected to severeimpact bythe opening spring when it is released. Since the upper block 38 of the opening spring has a short travel as compared with the opening stroke of the switch rod 1, this short travel being for the purpose of applying a'large accelerating force to the switchrod during the initial opening movement, the opening spring 3 during trip-free action may not engage the switch rod 1, the energy in that case being dissipated by the buffer spring 86.

With the mechanism in the second position of the cycle,'that is as shown in Fig.2, the switch rod 1 whichis lowered to the completely closed circuit position abuts the opening spring block- 38 through the roller ,37; In this position the opening spring 3 is in readiness to exert a power; ful upward opening thruston the switch rod 1 in response to actuation of the latch 46 by the tripping solenoid 45.- It will be apparent that the tripping solenoid 45 may be controlled in any well known manner in-response to abnormal circuit conditions or by ,a push button circuit, and'manually controlled means for actuating the latch 46 may likewise beemployed.

The third position of the cycle wherein the opening spring has been released is shown in Fig. 3. On release of the latch 46, the opening spring 3 causes collapse of the tripping toggle to the position shown and simultaneous counterclockwise rotationof'the cranks 51 and 32 initially accelerating the opening movement of the switchrod 1. Since the lever arm of crank 51 connected to, pin 54 is greater than the corresponding lever arm of crank 32 connected to pin 32, the'pin 49' moves counter-clockwise at a" greater rate than pin 32'. To compensate for this difference the pin and .slot connection between link 55 and pin 32' permits the toggle to stretch during the above described operation.

After the accelerating force has been applied the usual circuit breaker springs complete the circuit opening operation without difiiculty.

It will be noted that the spring 3 in discharging moves the contact 79 of the auxiliary switch 73- int0 engagement with contact '78 thereby completing 'a temporary circuit through the motor 4, It will likewise be noted that the springs of the mechanism are completely discharged and the toggles in thecollapsed releasedpositions thereof, the cams 6 and '7 still being in the first position shown in Fig. 1. When the circuit is completed through the auxiliary switch 73 however the cams, which are mounted on the common shaft 5' connected to the large gear 5, are rotated slowly in a clockwise direction with-the result that both rollers 15 and 42 very shortly fall from the corresponding high sides of the cams to the low sides as shown in Fig. 4. This causes lowering of the closing and opening springs and. stretching of the toggles to the original reset position shown in Fig. 1. Lowering of the opening spring block 38 consequently breaks the circuit at the auxiliary switch '73but initial rotation of the gear 5 has in the meantime moved the lug'7'7 out of engagement with the limit switch contact 75 so that the motor circuit is completed through this switch for the remainder of the spring charging operation. I

The aforesaid initial rotation of the cams likewise brings the roller 59 of the interlock lever 57 to the high side of its cam 60 thereby causing elevation of the rod 63 and movement of the locking levers 66 and 6 9 to their respective locking positions so that neither the-closing nor opening latches may be tripped.

The cams charging the closing and opening springs maybe of any-suitable design and are preferably of the constant power output type. As the gear 5 is slowly rotated in a clockwise direction by its driving motor, the rollers 15 and 42 are gradually elevated to the high sides of the respective cams until they have reached the position shown in' Fig. 1 wherein. the gear 5 has completed a whole revolution. When this position has been reached the lug 7'7 again opens the motor circuit through the contacts Hand- 75, overtravelof the motor mechanism due to inertia being prevented by a bump or high point 6 on the. cam 6. This arrangement serves to bring the mechanism to a stop due to the large force required further to compress the closing springs 2. It will likewise be noted that a complete revolution of the cams brings the interlock cam 60 to its original position wherein the roller 59 drops into the notch 60'. The resulting lowering of the rod 63 unlocks the closing spring latch 18, the prop '70 however holding the locking lever 69 in its looking out position.'

It will be noted that the switch-operating mechanism above described, as designed, provides for the usual operating requirements, as trip-free operation, and likewise through'its interlocking system insures a predetermined sequence of operation so that even an unex;

erienced or careless operator cannot damage the mechanism. For example, it is impossible for the operator to release the closing spring before the charging operation is complete or to energize the motor circuit until both springs have been discharged. Premature release of the closing spring would cause but incomplete closure of the breaker contacts, and severe burning of the same during the final closing which would obviously take place at very low speed. Inthe event that the motor circuit were energized after the closing spring had discharged, the roller 42 of the opening spring in riding over the high side of the cam would drop onto the low side of the cam withsuchforce ing out the opening spring until release of the closing spring insures a complete cycle of op eration since it is essential that the circuit breaker be open during charging of the springs.

In case of failure of the driving motor, suitable means, as a ratchet (not shown), may be associated with the gear 5 for they purpose of preventing reverse rotation of the cams. Manually operated means may be providedfor completing charging of the springs.

In Figs. 1 and 4 there is shown one form of manual operating means embodying my invention which may be used in case the motor is not available. The arrangement comprises a differentiallinkage operatively connected to the opening spring 3 so that overcharging of the opening spring beyond ,the point shown in Fig. 1 :is prevented. The manual operating means for rotating the spring-charging cams preferably comprises a chain and sprocket connection, the sprocket wheel 91 being mounted on a shaft which may be detachably keyed to an extension of the main pinion shaft 4. The sprocket wheel 91 "is connected through the chain 92 to the-sprocket wheel 93 which is 'mounted on a shaft 94 'on which is keyed the operating crank 95. Likewise keyed to the shaft 94 is alocking member 96 comprising an abutment arranged to beblocked .ina manner hereinafter described to prevent rotation of the crank 95 in a direction charging the springs. It will be apparent that counter-clockwise rotation of the crank'95 causes clockwise rotation of the spring charging'andinterlocking cams in the manner previously described.

For '.the purpose of convenience in use the sprocket wheel assembly'may be'mounted on a suitable frame which may be attached to the exterior of the mechanism frame and arranged to engage an extension of the pinion shaft 4.

The blocking means for rendering inoperative the manual operating means when the springs are fully charged comprises a differential linkage connected by a rod 97 ,to both the lower and upper opening spring cranks 40. and 51 respectively. The r0d'97 at its upper end is pivot- 'In the spring-charged position shown in Fig.

I the link 99' is raised so that it blocks further spring charging'operation and prevents riding of the cam rollers over the high faces of the cams. When the opening spring 3 is tripped in the usual manner, the interlocking means heretofore described insuring proper sequencev of operation, the consequent counter-clockwise rotation of crank 51 lowers the rod 97'and link so that the springs are ready for recharging.

During the resetting operation the cranks 49 and 51 obviously move in unison in clockwise direction causing movement of the arms 98 and 101 in'the same direction. Even though the.

link 99 is moved upwardly'to a certain extent the rod 97 maintains the outer or blocking endof the link 99 in a position too low to interfere with the abutment on member 96 until the spring charging operation is completed. Accordingly the springs may be recharged to the position shown in Fig. 1 wherein the difierential linkage again blocks further operation of the crank 95.

It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In switch operating mechanism including a spring and a manually operated cam arranged to act on one end of said spring for compressing the same, tripping means for holding stationary the other end of said spring, and means preventing overcharging of said spring by overtravel of said cam comprising a linkage operatively connected to opposite ends of said spring arranged so that further operation of said cam is blocked when said spring charging operation is completed.

2. In switch-operating mechanism including overcharging of the spring comprising a differ-- ential linkage operatively connected to opposite ends of said. spring, said linkage blocking said actuating when said spring is charged and movable to an inoperative position upon release of said spring.

4. In operating mechanism including an energy storing spring, tripping means for holding stationary one end of said spring, a manually operated cam arranged to act on the other end of said spring for charging the same, and means controlled. in accordance with the position of said spring blocking positively over-travel of said cam with respect to said spring.

CARL THUMIM. 

